The entire collection of all the hereditary factors of all individuals in a population

"Population" means a group of interbreeding individuals, which thus exchange hereditary material.

In plant breeding, it is possible to distinguish between primary, secondary and tertiary gene pools. Each primary gene pool comprises one cultivated species together with those species with which it readily cross-breeds. The secondary gene pool includes species that can be cross-bred only with difficulty. The tertiary gene pool comprises those species which can be cross-bred only by using advanced techniques such as embryo rescue.